The development of multidrug resistance (MDR) is a major cause of failure in chemotherapeutic management of cancer. Since all anticancer drugs ultimately exert their effect by triggering programmed cell death or apoptosis, our strategy to overcome MDR is focused on a multi-modal approach to: (1) increase systemic drug delivery efficacy and (2) lower the tumor apoptotic threshold. The preliminary studies show that co-administration of the lipid second messenger, ceramide (CER), along with paclitaxel (PTX) significantly enhanced the chemotherapeutic effect in vitro and in vivo in wild-type and resistant SKOV3 human ovarian adenocarcinoma models. In these sensitive and resistant tumor cells, since CER exerts the apoptotic effect through the mitochondrial pathway, we hypothesize that development of mitochondria-specific CER derivatives (mito-CER) would be even more potent in improving the pro-apoptotic response to PTX and other anticancer drugs. The mito-CER derivatives along with PTX will be co-administered in vitro and in vivo in epidermal growth factor receptor (EGFR)-targeted engineered biodegradable polymeric nanoparticle formulations. The specific aims of this R21 application are to: (1) synthesize mito-CER derivatives and formulate EGFR targeting peptide-modified poly(epsilon-caprolactone) (PCL) nanoparticle formulations of mito-CER and PTX. (2) evaluate mitochondria-specific intracellular delivery using Raman Spectral Imaging, cell-kill efficiency, and apoptotic response of single and combination PTX/mito-CER in SKOV3 (wild-type) and SKOV3TR (mdr-1 positive) human ovarian adenocarcinoma cells and (3) using a select mito-CER derivative, evaluate the in vivo antitumor efficacy and apoptotic response in SKOV3 and SKOV3TR tumor xenograft models established in female nu/nu (athymic) mice. The results of this study would be extremely valuable in the treatment of refractory tumors using a multifunctional nano-therapeutic approach that efficiently delivers the drug and can overcome cellular resistance. The multi-modal nanocarrier strategy proposed here would provide a translatable approach to overcome MDR in cancer patients. PUBLIC HEALTH RELEVANCE: Development of resistance to variety of chemotherapeutic agents is one of the major challenges in cancer therapy. Current strategy to overcome tumor drug resistance relies on combining different classes of anticancer drugs and by increasing the doses administered to patients. Since drug combinations and doses cannot be increases limitlessly without serious toxicity consequences, a rationale strategy to overcome tumor resistance is urgently needed. Since all chemotherapeutic agents ultimately exert their effect through a process called "Programmed Cell Death or Apoptosis", we propose to overcome drug resistance by lowering of the apoptotic threshold in tumor cells. Mitochondria-specific ceramide derivatives will be synthesized and co-administered with anticancer drug, paclitaxel, in sensitive and resistant human ovarian cancer to enhance the therapeutic effect. Using engineered polymeric nanoparticles, we will deliver this combination therapy to tumor mass as well as inside the cells for maximum apoptotic cell-kill effect.